High Frequency Generator Adaptive Power Control for Electrosurgery
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Solution Overview
Problem
High frequency generators used in electrosurgical cutting often struggle to achieve the necessary tissue impedance for arc ignition, especially with large-area electrodes, leading to prolonged waiting times for initial cutting support, which can be inconvenient for operators during procedures like endoscopic mucosal resection or polypectomy.
Innovation Solution
A high frequency generator with an arc detector and adaptive power control that delivers high power for initial cutting support, followed by reduced power for a cutting phase if an arc is ignited, or low power for a short pause if not, thereby shortening the time to arc ignition and eliminating unnecessary waiting times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high power is delivered continuously for initial cutting support, then arc ignition is achieved, but the time required for tissue drying and impedance increase becomes excessively long
Solution Approach 1:
The patent applies periodic action by delivering high power in repeated cycles rather than continuously. Each cycle consists of a high power phase followed by a pause, allowing the tissue impedance to increase incrementally with each cycle until arc ignition conditions are met. This periodic delivery pattern resolves the contradiction by achieving reliable arc ignition through cumulative thermal effect while minimizing total time through strategic pauses.
Solution Approach 2:
The patent applies preliminary action by delivering high power in advance during multiple initial cycles to progressively dry out the tissue and increase impedance before the actual cutting phase. This preliminary tissue preparation ensures that when the final arc ignition occurs, it happens rapidly and reliably, thus resolving the time contradiction by preparing the tissue in advance rather than during the critical cutting moment.
2Ease of operation
If a fixed pulse sequence with long pause intervals is used, then controlled cutting guidance is achieved, but unnecessary waiting times occur when arc ignition fails
Solution Approach 1:
The patent applies dynamics by making the pause interval duration adaptive rather than fixed. The pause interval automatically adjusts based on whether arc ignition was achieved in the previous high power cycle - it extends when ignition occurs to allow controlled cutting, and shortens when ignition fails to enable rapid retry. This dynamic adjustment resolves the contradiction by providing controlled guidance only when necessary while maximizing productivity when ignition challenges arise.
Solution Approach 2:
The patent applies feedback by using the arc ignition detection result from each cycle to determine the duration of the subsequent pause interval. The system monitors whether an arc was successfully ignited and uses this feedback information to adaptively control the timing of the next high power delivery cycle. This feedback mechanism resolves the contradiction by eliminating unnecessary waiting times while maintaining controlled guidance when needed.
3Speed
If high power is delivered to rapidly dry out large-area electrodes, then initial cutting characteristic is improved, but the thermal energy introduced is insufficient to achieve necessary impedance for arc ignition
Solution Approach 1:
The patent applies periodic action by delivering high power in repeated cycles rather than a single continuous application. Each cycle delivers thermal energy to dry the tissue, followed by a pause that allows the impedance to increase. The cumulative effect of multiple cycles progressively dries the tissue and builds up impedance, resolving the contradiction by achieving both rapid drying and sufficient impedance through repeated rather than single-phase energy delivery.
Solution Approach 2:
The patent applies preliminary action by using multiple high power cycles to progressively prepare the tissue through drying and impedance increase before the final arc ignition. This preliminary preparation in advance ensures that when the cutting phase begins, the tissue is already in the optimal state for reliable arc ignition, thus resolving the contradiction between drying speed and ignition capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the time to arc ignition and eliminates unnecessary waiting times during procedures, providing a more efficient and controlled electrosurgical cutting process.
Implementation Method 1
produce an arc firstly a very high level of power is delivered in order to rapidly dry out the body tissue bearing against the cutting electrode, and thereby rapidly to achieve a high tissue impedance necessary to produce an arc
Implementation Method 2
which has an arc detector and a power control which is so adapted that initially for a phase for initial cutting support it causes the delivery of a high output power
Data Source
AI summary
A high frequency generator connected to an electrosurgical instrument comprising an electrical output terminal, a power source electrically connected to the output terminal, an arc detector, and a power control for controlling the electrical power delivered through the output terminal. The power control initially causes the delivery of a high output power for a phase for initial cutting support and thereafter, if ignition of an arc has occurred for a predetermined period of time to cause the delivery of reduced or no power and subsequently for a predetermined period of time to cause the delivery of reduced or no power at which no arc occurs, or if no ignition of an arc has occurred during the phase for initial cutting support, to cause the delivery of reduced or no power for a predetermined period of time of a short pause interval.